Delta bath cartridge removal
I have a single handle Delta bath faucet valve whose cartridge needs to be replaced because it is dripping. It is about 4 years old or so. I can find no part number anywhere on it.
I got all the parts removed, down to removing the brass collar that holds the cartridge in place. NO GO! I put a big monkey wrench on it - nothing. I soaked it with silicon lube - nope. I then tried white vinegar, in case water deposits were the culprit -- NOPE! I thought I was going to rip the plumbing out of the wall.
I'm stuck. No more ideas. I hate to call an expensive plumber because I can't get this thing off. What can I do?